1. The Field of the Invention
This invention relates to novel, yellow ortho, ortho' dihydroxy azomethine dyes having a silver halide developing capability.
2. Description of the Prior Art
Yellow dyes having a silver halide developing capability, e.g., a silver halide developing substituent are known to the art. Such dyes, commonly referred to as "dye developers," are disclosed in the following U.S. Pat. Nos. among others; 3,134,764; 3,135,604; 3,135,734, 3,141,772; 3,183,090; 3,309,199; 3,424,742, 3,597,200; 3,705,184 and 3,752,836. Of these patents, U.S. Pat. Nos. 3,597,200; 3,705,184 and 3,752,836 particularly relate to ortho, ortho' dihydroxy azomethine dyes conforming to the following general formula: ##STR2## WHERE: A is a phenyl or naphthyl radical and B is a phenyl, naphthyl or heterocyclic radical and, as disclosed in those patents, the radicals of either the A or B moiety may contain a silver halide developing substituent. However, the particularly preferred embodiments of those patents are 1:1 chrome complexes of yellow, ortho, ortho' dihydroxy azomethines of Formula 1 with a substantially colorless ligand which is the moiety providing the silver halide developing substituent for the complexed dyes. Details relating to the preferred colorless ligands having a silver halide developing substituent can be found in U.S. Pat. No. 3,629,336. The particularly preferred 1:1 chrome complexed yellow azomethine dyes as disclosed in U.S. Pat. Nos. 3,597,200, 3,705,184 and 3,752,836 can be described by the following general formulae: ##STR3## WHERE: A and B are as defined before; L represents molecules that can satisfy the coordination sphere of chromium and can be H.sub.2 O, (CH.sub.3).sub.2 NHCO among others; X represents the atoms needed to complete an aliphatic, aromatic or heterocyclic ring and these rings may contain a silver halide developing substituent; R and R' may be alkyl, fluoroalkyl, alkoxyalkyl, phenyl, phenylamino, etc; R.sup.2 may be hydrogen, lower alkyl, phenyl or a radical comprising a silver halide developing substituent and R.sup.3 may be hydrogen, lower alkyl or a radical comprising a silver halide developing substituent or R.sup.3 may be hydroxyl but if X represents the atoms needed to complete a 5 or 6 membered ring, R.sup.3 cannot be hydroxyl.
A particularly effective class of 1:1 chrome complexed, yellow axomethine dye developers are described in U.S. Pat. No. 3,705,184 and especially preferred are the 1:1 chrome complexed azomethines of the following general formula: ##STR4## where, m and n are 1 or 2, (alkoxy) has from 1-8 carbon atoms and --alkylene-- has from 1-6 carbon atoms.
1:1 chrome complexed yellow azomethine dyes of the above Formula 4 have excellent performance characteristics in terms of color as well as stability. In fact, a chrome complexed azomethine of Formula 4 which conforms to the following specific formula has enjoyed extensive success in commercial diffusion transfer, photographic film units. ##STR5##
The present invention presents to the art, novel, yellow ortho, ortho' dihydroxy azomethine dyes integrated with a silver halide developing capability. As a class, the novel yellow azomethine dyes of the present invention provide excellent dye developers, especially chrome complexed dye developers having performance characteristics substantially equivalent to and in some respects superior to yellow azomethine dye developers known to the art.